From: Brad Jorsch <bjorsch@wikimedia.org>
Date: Wed, 14 Sep 2016 14:13:10 +0000 (-0400)
Subject: API: Force straight join for prop=linkshere|transcludedin|fileusage
X-Git-Tag: 1.31.0-rc.0~5528^2
X-Git-Url: http://git.cyclocoop.org/%22%20.%20generer_url_ecrire%28%22suivi_revisions%22%29%20.%20%22?a=commitdiff_plain;h=81912c3ef943d8a702ea60aa67f4abe9e22cdabe;p=lhc%2Fweb%2Fwiklou.git

API: Force straight join for prop=linkshere|transcludedin|fileusage

MySQL (or at least 5.5.5-10.0.23-MariaDB) chooses a really bad query plan if it
thinks there will be more matching rows in the linktable than are in page. Use
STRAIGHT_JOIN here to force it to use the intended, fast plan. See T145079 for
details.

Bug: T145079
Change-Id: I1a363450b818a049938145d0feb207c9894d2a49
---

diff --git a/includes/api/ApiQueryBacklinksprop.php b/includes/api/ApiQueryBacklinksprop.php
index 236fb9e06c..8e89c32e50 100644
--- a/includes/api/ApiQueryBacklinksprop.php
+++ b/includes/api/ApiQueryBacklinksprop.php
@@ -264,6 +264,12 @@ class ApiQueryBacklinksprop extends ApiQueryGeneratorBase {
 			}
 		}
 
+		// MySQL (or at least 5.5.5-10.0.23-MariaDB) chooses a really bad query
+		// plan if it thinks there will be more matching rows in the linktable
+		// than are in page. Use STRAIGHT_JOIN here to force it to use the
+		// intended, fast plan. See T145079 for details.
+		$this->addOption( 'STRAIGHT_JOIN' );
+
 		$this->addOption( 'LIMIT', $params['limit'] + 1 );
 
 		$res = $this->select( __METHOD__ );